scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2021 ◽  
Vol 136 (2) ◽  
pp. 411-429
Author(s):  
M. P. Yutkin ◽  
C. J. Radke ◽  
T. W. Patzek
Keyword(s):  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Design Tool ◽  
Mineral Dissolution ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions ◽  
Water Wettability

AbstractHigher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. In addition, calcite mineral reacts with aqueous solutions and can alter substantially the composition of injected water by mineral dissolution. Carefully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood process, where some finely tuned brine compositions can improve flood performances, whereas others cannot. We present a 1D reactive transport numerical model that captures the changes in injected compositions during water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion. At typical calcite reaction rates, local equilibrium is established immediately upon injection. In SI, we validate the reactive transport model against analytic solutions for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. Accordingly, using an open-source algorithm (Charlton and Parkhurst in Comput Geosci 37(10):1653–1663, 2011. 10.1016/j.cageo.2011.02.005), we outline a design tool to specify chemical/brine flooding formulations that correct for composition alteration by the carbonate rock. Subsequent works compare proposed theory against experiments on core plugs of Indiana limestone and give examples of how injected salinity compositions deviate from those designed in the laboratory for water-wettability improvement.

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

scholarly journals Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

2021 ◽  
Author(s):  
Torben Prill ◽  
Cornelius Fischer ◽  
Pavel Gavrilenko ◽  
Oleg Iliev
Keyword(s):  
Contaminated Soils ◽  
Reactive Transport ◽  
Transport Model ◽  
Crystal Surface ◽  
Reaction Rates ◽  
Surface Reactivity ◽  
Reservoir Rock ◽  
Intrinsic Variability ◽  
Multiple Systems ◽  
The Difference

AbstractCurrent reactive transport model (RTM) uses transport control as the sole arbiter of differences in reactivity. For the simulation of crystal dissolution, a constant reaction rate is assumed for the entire crystal surface as a function of chemical parameters. However, multiple dissolution experiments confirmed the existence of an intrinsic variability of reaction rates, spanning two to three orders of magnitude. Modeling this variance in the dissolution process is vital for predicting the dissolution of minerals in multiple systems. Novel approaches to solve this problem are currently under discussion. Critical applications include reactions in reservoir rocks, corrosion of materials, or contaminated soils. The goal of this study is to provide an algorithm for multi-rate dissolution of single crystals, to discuss its software implementation, and to present case studies illustrating the difference between the single rate and multi-rate dissolution models. This improved model approach is applied to a set of test cases in order to illustrate the difference between the new model and the standard approach. First, a Kossel crystal is utilized to illustrate the existence of critical rate modes of crystal faces, edges, and corners. A second system exemplifies the effect of multiple rate modes in a reservoir rock system during calcite cement dissolution in a sandstone. The results suggest that reported variations in average dissolution rates can be explained by the multi-rate model, depending on the geometric configurations of the crystal surfaces.

scholarly journals Chemical Compositions in Modified Salinity Waterflooding of Carbonate Reservoirs -- Experiment

2021 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Calcium Carbonate ◽  
Ion Exchange ◽  
Crude Oil ◽  
Oil Recovery ◽  
Carbonate Rock ◽  
Single Phase ◽  
Theoretical Framework ◽  
Mineral Dissolution ◽  
High Dispersion ◽  
Carbonate Dissolution

<br>Modified or low-salinity waterflooding of carbonate oil reservoirs is of considerable economic interest because of potentially inexpensive incremental oil<br>production. The injected modified brine changes the surface chemistry of the carbonate rock and crude oil interfaces and detaches some adhered crude oil.<br>Composition design of the modified brine to enhance oil recovery is determined by labor-intensive trial-and-error laboratory corefloods. Unfortunately, limestone,<br>which predominantly consists of aqueous-reactive calcium carbonate, alters injected brine composition by mineral dissolution/precipitation. Accordingly, the rock reactivity<br>hinders rational design of the tailored brine to improve oil recovery. <br>Previously, we presented a theoretical analysis of 1D, single-phase brine injection into calcium carbonate-rock that accounts for mineral dissolution, ion<br>exchange, and dispersion (Yutkin et. al 2021). Here we present the results of single-phase waterflood-brine experiments that verify the theoretical framework. We show that concentration histories eluted from Indiana limestone cores possess features characteristic of fast calcium<br>carbonate dissolution, 2:1 ion exchange, and high dispersion. The injected brine reaches chemical equilibrium inside the porous rock even at<br>injection rates higher than 1000 ft/day. Ion exchange results in salinity waves observed experimentally, while high dispersion is responsible for long<br>concentration history tails. <br>Using the verified theoretical framework, we briefly explore how these processes modify aqueous-phase composition during the injection of designer brines into a calcium-carbonate reservoir. Because of high salinity of the initial and injected brines, ion exchange affects injected concentrations only in<br>high surface area carbonates/limestones, such as chalks. Calcium-carbonate dissolution only affects aqueous solution pH. The rock surface composition is affected by all processes.<br><br>

scholarly journals Chemical Compositions in Modified Salinity Waterflooding of Calcium Carbonate Reservoirs: Experiment

2022 ◽  
Author(s):  
M. P. Yutkin ◽  
C. J. Radke ◽  
T. W. Patzek
Keyword(s):  
Calcium Carbonate ◽  
Ion Exchange ◽  
Crude Oil ◽  
Oil Recovery ◽  
Carbonate Rock ◽  
Single Phase ◽  
Mineral Dissolution ◽  
High Dispersion ◽  
Carbonate Dissolution ◽  
Calcium Carbonate Dissolution

AbstractModified or low-salinity waterflooding of carbonate oil reservoirs is of considerable economic interest because of potentially inexpensive incremental oil production. The injected modified brine changes the surface chemistry of the carbonate rock and crude oil interfaces and detaches some of adhered crude oil. Composition design of brine modified to enhance oil recovery is determined by labor-intensive trial-and-error laboratory corefloods. Unfortunately, limestone, which predominantly consists of aqueous-reactive calcium carbonate, alters injected brine composition by mineral dissolution/precipitation. Accordingly, the rock reactivity hinders rational design of brines tailored to improve oil recovery. Previously, we presented a theoretical analysis of 1D, single-phase brine injection into calcium carbonate-rock that accounts for mineral dissolution, ion exchange, and dispersion (Yutkin et al. in SPE J 23(01):084–101, 2018. 10.2118/182829-PA). Here, we present the results of single-phase waterflood-brine experiments that verify the theoretical framework. We show that concentration histories eluted from Indiana limestone cores possess features characteristic of fast calcium carbonate dissolution, 2:1 ion exchange, and high dispersion. The injected brine reaches chemical equilibrium inside the porous rock even at injection rates higher than 3.5 $$\times$$ × 10$$^{-3}$$ - 3  m s$$^{-1}$$ - 1 (1000 ft/day). Ion exchange results in salinity waves observed experimentally, while high dispersion is responsible for long concentration history tails. Using the verified theoretical framework, we briefly explore how these processes modify aqueous-phase composition during the injection of designer brines into a calcium-carbonate reservoir. Because of high salinity of the initial and injected brines, ion exchange affects injected concentrations only in high surface area carbonates/limestones, such as chalks. Calcium-carbonate dissolution only affects aqueous solution pH. The rock surface composition is affected by all processes.

scholarly journals Chemical Compositions in Modified Salinity Waterflooding of Carbonate Reservoirs -- Experiment

2021 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Calcium Carbonate ◽  
Ion Exchange ◽  
Crude Oil ◽  
Oil Recovery ◽  
Carbonate Rock ◽  
Single Phase ◽  
Theoretical Framework ◽  
Mineral Dissolution ◽  
High Dispersion ◽  
Carbonate Dissolution

<br>Modified or low-salinity waterflooding of carbonate oil reservoirs is of considerable economic interest because of potentially inexpensive incremental oil<br>production. The injected modified brine changes the surface chemistry of the carbonate rock and crude oil interfaces and detaches some adhered crude oil.<br>Composition design of the modified brine to enhance oil recovery is determined by labor-intensive trial-and-error laboratory corefloods. Unfortunately, limestone,<br>which predominantly consists of aqueous-reactive calcium carbonate, alters injected brine composition by mineral dissolution/precipitation. Accordingly, the rock reactivity<br>hinders rational design of the tailored brine to improve oil recovery. <br>Previously, we presented a theoretical analysis of 1D, single-phase brine injection into calcium carbonate-rock that accounts for mineral dissolution, ion<br>exchange, and dispersion (Yutkin et. al 2021). Here we present the results of single-phase waterflood-brine experiments that verify the theoretical framework. We show that concentration histories eluted from Indiana limestone cores possess features characteristic of fast calcium<br>carbonate dissolution, 2:1 ion exchange, and high dispersion. The injected brine reaches chemical equilibrium inside the porous rock even at<br>injection rates higher than 1000 ft/day. Ion exchange results in salinity waves observed experimentally, while high dispersion is responsible for long<br>concentration history tails. <br>Using the verified theoretical framework, we briefly explore how these processes modify aqueous-phase composition during the injection of designer brines into a calcium-carbonate reservoir. Because of high salinity of the initial and injected brines, ion exchange affects injected concentrations only in<br>high surface area carbonates/limestones, such as chalks. Calcium-carbonate dissolution only affects aqueous solution pH. The rock surface composition is affected by all processes.<br><br>

scholarly journals Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 84-101 ◽  
Author(s):  
Maxim P. Yutkin ◽  
Himanshu Mishra ◽  
Tadeusz W. Patzek ◽  
John Lee ◽  
Clayton J. Radke
Keyword(s):  
Ionic Strength ◽  
Ion Exchange ◽  
Crude Oil ◽  
Surface Charge ◽  
Double Layer ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Diffuse Double Layer ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Summary Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of calcite bulk and surface equilibria draws several important inferences about the proposed LSW oil-recovery mechanisms. Diffuse double-layer expansion (DLE) is impossible for brine ionic strength greater than 0.1 molar. Because of rapid rock/brine equilibration, the dissolution mechanism for releasing adhered oil is eliminated. Also, fines mobilization and concomitant oil release cannot occur because there are few loose fines and clays in a majority of carbonates. LSW cannot be a low-interfacial-tension alkaline flood because carbonate dissolution exhausts all injected base near the wellbore and lowers pH to that set by the rock and by formation CO2. In spite of diffuse double-layer collapse in carbonate reservoirs, surface ion-exchange oil release remains feasible, but unproved.

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